Electrical coil



April 9, 1935. O D N' 1,997,020

ELECTRICAL COIL Filed July 15, 1934 [M A-470R- OTTO 5oz. DAN

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Patented Apr. 9, 1935 UNITED STATE PATENT OFFICE v ELECTRICAL con.

Otto Soldan, Berlin, Germany, assignor to Siemens & Halske Aktiengesellschaft, Siemens stadt, near Berlin, Germany Application July 13, 1934, Serial No. 734,936 In Germany August 11, 1933 4 Claims. (01. 175-21) 5 body of great strength together with a structure which is simple to manufacture, as well as being cheaper to assemble with other portions of a magnet system.

According to the invention, this is achieved by providing a core that is filled out with insulated extruded material which forms the coil discs outside the core, and which also serves for mounting other parts held together by the insulating extruded mass which parts are utilized for fixing and contact purposes.

The invention is described in detail by reference to an embodiment suitable for use in a telephone receiver which is shown on the drawing, in section in Fig. l and in plan view in Fig. 2, as seen from the top of Fig. l.

The core I, consisting of a thin-walled, slotted plate is suitably bent into a cylinder and connected-by flanging over at its lower end to ametallic plate 2 of magnetic material. This plate 2,- which may be threaded round its periphery, serves for fixing the entire magnet system in thereceiver casing or the like, and is also provided with holes 3 for mounting the permanent mag- ;nets (not shown here) which may be either .U- shaped or of the straight bar type. A thin disc 4 of non-magnetic and preferably insulating material is provided'on the upper side of the plate 2 and held in position by the securing meansfoa the magnets. This plate is forintroducing a gap into the magnetic circuit since in the particular construction visualized a pot-shaped magnetic member (not shown) is mounted on'thebase plate 2 and co-operates with a circular. armature mounted on the diaphragm of the receiver. This arrangement produces a partial separationof the magnetic circuits carrying steady and alternating flux which is found to possess certain advantages. 0n the lower side of the plate 2 but separated from it by insulating material is adivided contact disc 5 to which are connectedthe ends of the winding (not shown) so that connection maybe made to an external circuit by means of springs. The plate Bis secured in position by the tongues 6 which are bent up through the plate 2,

The interior of the core I is filled out with insulating extruded material 7 which passes through the mounting plate 2 at its central cutout portion, so that both the insulating disc 4 and also the mounting plate 2 form with the core I an intimately "connected-together single structure. In addition, the coil discs or cheeks 8 for retaining the winding, (not shown) are formed by the insulating material 1 by means of which, at the same time, the exterior walling of 10 'sheet core l is insulated. The finishing of such coil bodies can be very much simplified by the employment of insulating extruded material as an insulating mass, and this process, therefore, is

particularly adapted to mass production; an ex- 15 tremely durable coil body, stiffening the thin sheet core, being'thereby attained.

Having described the invention, what is con= sidered to be new and is desired to be protected by Letters Patent will be set ing claims.

What is claimed is: 1. In an electrical coil, a metallic hollow core, insulated extruded material filling said core, coil forth in the follow- 20 discs formed from said material on each end of 25 said core, and mounting means held together by said insulated material.

2. In an electrical coil, a hollow core, insulated extruded material in which said'core is imbedded,

of said core, and mounting means, contact means and other insulating means held together by said insulated extruded materialto said core.

3. In an electrical coil, a hollow core, insulated coil discs formed from said material on each end an extruded material inside and around said core, 35

coll discs formed on each end of said core from said insulated material, a mounting plate, a contact plateseparated from said mounting plate by said insulating material, an insulated plate on said mounting plate, said insulating extruded 4o material holding said contact plate, said mounting plate, and said insulating plate together on one end of said core.

4. In an electrical coil, a hollow core, insulated extruded material in which said core is imbed- 45 ded, coil discs formed of said insulated material on each end of said core, and a plurality of plates supported by and held together on one end of said core by said insulated material.

OTTO SOL-DAN. 

